New species of river dolphin born of Amazon rapids

A NEW species of river dolphin has been found, the first of its kind for a century.

Tomas Hrbek of the Federal University of Amazonas in Manaus, Brazil, took DNA from river dolphins in the Araguaia and Tocantins rivers. He found they differed from all other species in Brazil. He calls the species Inia araguaiaensis (PLoS One, DOI: 10.1371/journal.pone.0083623).

Its genes suggest that the species formed 2.08 million years ago, when the Araguaia-Tocantins basin was cut off from the rest of the Amazon river system by huge rapids and waterfalls, isolating the dolphins from their fellows.

"It's exciting evidence for a previously unrecognised species within the ancient lineage of Amazon river dolphins," says Scott Baker of Oregon State University in Newport. "Yet it's already rare, and its habitat is now fragmented by dams."

This article appeared in print under the headline "Brazilian dolphin born of rapids"

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